The present application claims the benefit under 35 U.S.C. xc2xa7119 of French application 00/12817 filed Oct. 6, 2000, the disclosure of which is hereby incorporated by reference.
(i) Field of the Invention
The present invention relates to a novel vaccine formulation comprising at least one antigen, in particular an antigen of viral, bacterial or parasitic origin, and the method for its preparation.
Currently, the customary vaccines have a storage life which does not exceed 18 to 24 months at +4xc2x0 C., whether they are oil-based or aqueous. Trials carried out by the Institute for Animal Health (IAH) in Great Britain have shown that oil-based vaccines frozen at xe2x88x9220xc2x0 C. and at xe2x88x9270xc2x0 C. lost their activity. Accordingly, commercial vaccines are labeled in this country with the label: xe2x80x9cnot to be frozen.xe2x80x9d
Antigens may be stored for longer periods, up to 15 years, at very low temperature, in the form of concentrates. It is essential, in this case, to have means for formulating vaccines close to their storage site in order to avoid loss of time when the vaccine is urgently required.
These considerations have led the applicant to support work aimed at developing vaccines which can be stored for several years, and which are ready to use after thawing.
According to a first aspect, the subject of the invention is a composition comprising at least one antigenic medium and at least one adjuvant, characterized in that:
(a) the antigenic medium or the antigenic media constitute phases which are distinct from the adjuvant phase or from the adjuvant phases when the composition is in the solid state, and
(b) the composition is in the liquid state when its temperature is greater than or equal to 4xc2x0 C.
The expression distinct phases indicates that, in the composition which is the subject of the present invention, none of the phases is, in the solid state, included, dissolved, emulsified or dispersed in another.